Plastic rail insulator for concrete tie fastenings

ABSTRACT

An insulator has a platelike body portion and an integral end flange in abutting contact with the top side and the edge of a rail base flange, respectively, and a metal holddown clip or clamp plate is bolted to a concrete tie with one portion thereof in overlying abutting contact with the body portion of said insulator and another portion juxtaposed to said end flange. At each side of the insulator and extending along said body portion and said end flange is a shoulder in closely spaced relation to the corresponding side of said clip to prevent the insulator from moving or twisting from between the clip and the rail in either direction that the rail may tend to move longitudinally during expansion and contraction of the rail and during passage of a train or the braking of a train.

United States Patent Garwood N. Burwell [72] Inventor Madison, NJ. [21] Appl. No. 837,008 [22] Filed June 25, 1969 [45] Patented Oct. 5, 1971 [73] Assignee The Rails Company l-iamden, Conn.

[54] PLASTIC RAIL INSULATOR FOR CONCRETE TIE FASTENINGS 1 Claim, 7 Drawing Figs.

[52] U.S. Cl 238/310, 238/283, 238/349 [51] lnt.C1 .Q E0lb 9/30 [50] Field of Search 238/349, 351, 283, 310

[56] References Cited UNITED STATES PATENTS 3,223,328 12/1965 Moses et al. 238/349 3,387,781 6/1968 Moses et a1. 238/283 3,460,756 8/1969 Sanson 238/349 FORElGN PATENTS 1,058,481 11/1963 France 238/283 1,126,697 9/1968 Great Britain 238/349 Primary ExaminerArthur L. La Point Assistant ExaminerRichard A. Bertsch Attorney-Harry B. Rook ABSTRACT: An insulator has a platelike body portion and an integral end flange in abutting contact with the top side and the edge of a rail base flange, respectively, and a metal holddown clip or clamp plate is bolted to a concrete tie with one portion thereof in overlying abutting contact with the body portion of said insulator and another portion juxtaposed to said end flange. At each side of the insulator and extending along said body portion and said end flange is a shoulder in closely spaced relation to the corresponding side of said clip to prevent the insulator from moving or twisting from between the clip and the rail in either direction that the rail may tend to move longitudinally during expansion and contraction of the rail and during passage of a train or the braking of a train.

PATENTED um 51971 Q, S J

N. M N

ATTORNEY I INVIL'N'IUK woop h. Burwell,

PLASTIC RAIL INSULATOR FOR CONCRETE TIE FASTENINGS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a device for electrically insulating railroad rails, clips and bolts from the interior of a concrete tie. It is generally known, that steel cables are used in the construction of concrete ties and, along with most electrical resistance rating of concrete, contribute to a low electrical resistance between the two rails that the trains run on. In modern signal circuits is is necessary to maintain the electrical resistance of the two rails in order to ensure satisfactory, safe operation of the signal circuits that include the rails, as well as the basic track circuit that indicates the presence of a train.

2. Prior Art According to past practice, insulating elements have been I employed with washer portions between the clips and the boltheads or nuts and with spigot portions lining the holes in the metal clips for example as shown in US. Pat. No. 3,246,843. Later L-shaped blocks of a plastic insulating material have been proposed to provide insulating between the longer arm of a double-armed metal spring clip and the top surface of the rail base flange and also to insulate the shorter arm of the clip from the edge of the rail base flange. The assembly of the insulating bushings with holddown clip and bolt is time-consuming and expensive, and the bushings quickly wear so that the insulating functions are impaired if not destroyed and the holddown clip becomes loosened with the consequent danger to operation of trains over the tracks. With the L-shaped insulator block, the normal longitudinal movements of the rail during expansion and contraction thereof and the passage of a train or the braking of a train tends to twist the insulator from its position between the clip and the rail base flange, thereby loosening the holddown assembly which results in contact of the clip with the rail base and consequent lowering or eliminating of the electrical resistance to an unsafe level; and the complete dislocation of the insulator causes the loosening of the holddown assembly to such an extent as to permit the displacement of the rail from its normal position with resulting danger to the operation of trains.

SUMMARY The primary object of the present invention is to provide an insulated rail fastener which shall overcome the abovedescribed deficiency of and objections to the heretofore devices.

More particularly the invention contemplates a plastic insulator having body portion and an integral end flange in abutting contact with the top side and the edge of a rail base flange, respectively. A shoulder extends outwardly from the body portion and the flange at each side of the insulator, and the main portion and the auxiliary portion of a metal spring clip are disposed between and in closely spaced relation to said shoulders so that any tendency of the insulator to move with the rail upon longitudinal movement of the rail in either direction, in any such manner as to slide or twist the insulator from between the clip and the rail is prevented by abutment of said shoulders with the corresponding sides of the clip.

A BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is the top plan view of an insulated rail fastening for concrete ties embodying the invention, portions of the rail being broken away with the web thereof being shown in section;

FIG. 2 is a vertical sectional view approximately on the plane of the line 2-2 of FIG. 1, illustrating the holddown clip and insulators in side elevation;

FIG. 3 is a fragmentary vertical sectional view on the plane ofthe line 3-3 of FIG. 1;

FIG. 4 is a perspective view of the insulator;

FIG. 5 is a fragmentary top plan view similar to FIG. 1 of a form of the invention designed for use where the rail fastening is juxtaposed to a rail joint, one of the joint plates and the rail being broken away and shown in section;

FIG. 6 is an elevational view of the rail fastener shown in FIG. 5, and

FIG. 7 is a perspective view of the insulator shown in FIGS. 5 and 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specifically describing the embodiment of the invention shown in FIGS. 1 to 4, inclusive, the reference character A designates a railway rail the base flanges B of which are secured on a reinforced concrete tie C of known construction. Disposed between the bottom surfaces of the flanges B and the top surface of the tie C is a pad or sheet D of resilient electrical insulating material, for example rubber or polyethylene. The base flange B of the rail is here shown as pressed and firmly held against the pad D by rail-fastening devices E and F that are installed, respectively, on the inside or gauge side of the rail and on the outside or field side of the rail.

The fastening device E includes a holddown clip I of generally known construction which is formed of a strip of spring steel bent in such a manner as to have a main portion and an auxiliary portion, here shown as two superposed parallel arms 2 and 3 connected by a loop portion 4. The loop portion is seated in a recess 5 in the tie and the arms 2 and 3 have aligned holes 6 through which passes fastening means 7 which in the present instance consists of a capscrew screwed into a bushing 8 imbedded in the tie, although instead of a screw threaded into a bushing the fastening means may be a bolt I0 having one end rigidly secured in the tie and having a nut II threaded on its other end as shown in FIGS. 5 and 6.

In accordance with the invention an insulator G is interposed between the clip 1 and the rail base flange. This insulator may be formed of any suitable electrical insulating synthetic plastic material possessing sufficient density to satisfactorily withstand the compressive force of the fastening device it is used with, as well as having sufficient strength to resist the lateral thrust of the rail against the fastening device. The plastic material while having these physical properties must also possess a high degree of electrical resistivity when exposed to certain conditions, for example water, sunlight, and high and low temperatures A preferred material has been found to be Nylon; elastomers of various types may be found suitable if the above-mentioned conditions can be satisfied.

The insulator has a body portion 12 and an integral end flange 13, and in use the insulator is interposed between the clip 1 and the rail base flange with the body portion I2 in overlying abutting contact with the top surface 14 of the rail flange and with the end flange 13 of the insulator in contact with edge 15 of the rail flange. The top surface of the body portion 12 is beveled or concave to approximately conform to the shape of the main portion or arm 2 of the clip which is pressed into contact with the insulator by the screw 7 as best shown in FIG. 3. The end of the auxiliary portion or arm 3 is in juxtaposed relation to the end flange 13.

At each side of the insulator is a shoulder that extends along the body portion and the end flange, and the shoulder may be continuous along the body portion and flange as shown for example in FIG. 7 or maybe in two segments 16 and 17 extending along the body portion and the end flange, respectively, as best shown in Hg. 4. When the rail fastening is assembled, the shoulders are in closely spaced opposed relation to the sides of the clip as best shown in FIG. 1 so that any tendency of the insulator to move in either direction with the rail upon longitudinal movement of the rail in either direction as a result of expansion or contraction or during passage of a train or the braking of a train, in any such manner as to displace the insulator from between the clip and the rail flange, is positively prevented by abutment of one shoulder or the other with the corresponding side of the clip. Therefore, the danger incident to displacement of the insulator in such a way as to permit direct contact of the clip with the rail flange, is practically eliminated. It is particularly important that any twisting motion that would tend to break the body portion 12 away from the end flange is prevented and that the integrity of the insulator is maintained throughout long periods of use of the rail fastening with repeated longitudinal movement of the rail flange relative to the insulator.

The same general combination of insulator and clip is utilized on the field side of the track but in such cases usually the clip has a difl'erent form as shown at the right-hand side of FIGS. 1 and 2 where the clip H has a main portion 19 and auxiliary portion 20 and a base portion 21 whose outer end portion is curved as indicated at 22 to seat in a recess 23 that corresponds to the recess 5. A capscrew 24 secures the clip to the tie C.

Sometimes the bolts or screws 7 or 10 occur in the tie adjacent a rail joint, in which cases the shapes of the insulator and the clip are modified as shown in FIGS. and 6. Here one of the rail joint plates is designated l and is secured to the joint plate at the opposite side of the rail (not shown) by the usual bolt K. The joint plate has a foot flange L formed with a top surface 25 and a longitudinal edge 26. The insulator M has a body portion 27 and an end flange 28 and shoulders 29 extending along the body portion and the end flange to abut respectively the top surface 25 and edge 26 of the flange L. The clip has a main portion 30 and an auxiliary portion 31 which contact respectively the portion 27 and the end flange 28 of the insulator, and the clip also has a base portion 32 whose curved outer end 33 is pressed into the recess 34 in the tie by the nut 11 screwed onto the bolt which is imbedded in the tie.

It will be understood by those skilled in the art that modifications and changes can be made in the specific shapes and combinations of the insulator and clip within the spirit and scope of the invention.

What is claimed is:

1. ln a railway rail-holding device for use with a concrete railway tie and a rail having base flanges supported thereon, each of which has a top side and an edge angularly related to said top side, said tie having an abutment seat spaced from the edge of one rail base flange, a metal clip having a portion seated in said abutment seat and having a main portion overlying the top side of said rail base flange, and having an auxiliary portion juxtaposed to the edge of said base flange, an insulator comprising a rigid molded block of insulating material having a body portion disposed between the rail flange and the main portion of the clip and an end flange projecting angularly from said body portion and disposed between said auxiliary portion of the clip and the edge of the rail flange, said insulator normally being free for adjusting movement relatively to said tie and said rail flange and said fastening means, and said insulator also having parallel shoulders one at each side thereof, said shoulders having portions projecting from and extending along the top surface of said body portion of the insulator and receiving between them said main portion of said clip, and said shoulders having other portions projecting from and extending along the outer surface of said end flange and receiving said auxiliary portion of said clip between them, said main portion of said auxiliary portion of the clip having aligned holes therethrough, and means including a part secured in the tie and passing through said holes and another part abutting the top of said main portion of the clip for pressing the main portion OF the clip tightly against said body portion of the insulator and simultaneously pressing said insulator tightly against the rail base flange, said shoulder portions of the insulator being in closely spaced relation to the sides of the clip and the abutment of said shoulders with the sides of the clip holding the insulator against movement by and with the rail upon longitudinal movement of the rail and thereby prevents the insulator from being slid or twisted or displaced from between the clip and the rail. 

1. In a railway rail-holding device for use with a concrete railway tie and a rail having base flanges supported thereon, each of which has a top side and an edge angularly related to said top side, said tie having an abutment seat spaced from the edge of one rail base flange, a metal clip having a portion seated in said abutment seat and having a main portion overlying the top side of said rail base flange, and having an auxiliary portion juxtaposed to the edge of said base flange, an insulator comprising a rigid molded block of insulating material having a body portion disposed between the rail flange and the main portion of the clip and an end flange projecting angularly from said body portion and disposed between said auxiliary portion of the clip and the edge of the rail flange, said insulator normally being free for adjusting movement relatively to said tie and said rail flange and said fastening means, and said insulator also having parallel shoulders one at each side thereof, said shoulders having portions projecting from and extending along the top surface of said body portion of the insulator and receiving between them said main portion of said clip, and said shoulders having other portions projecting from and extending along the outer surface of said end flange and receiving said auxiliary portion of said clip between them, said main portion of said auxiliary portion of the clip having aligned holes therethrough, and means including a part secured in the tie and passing through said holes and another part abutting the top of said main portion of the clip for pressing the main portion OF the clip tightly against said body portion of the insulator and simultaneously pressing said insulator tightly against the rail base flange, said shoulder portions of the insulator being in closely spaced relation to the sides of the clip and the abutment of said shoulders with the sides of the clip holding the insulator against movement by and with the rail upon longitudinal movement of the rail and thereby prevents the insulator from being slid or twisted or displaced from between the clip and the rail. 